1. Field of the Invention
The invention relates to flow-straighteners for turbomachines, especially flow-straighteners of the type having large-sized blades and intended for the fans of bypass turbojet engines, and particularly relates to the construction of the blades of the flow-straightener.
2. Summary of the Prior Art
In order to achieve mass reductions and to meet operational conditions demanding good mechanical characteristics, anti-vibration properties and impact resistance, it is known to make hollow blades of large chord for the fan rotor of bypass turbojet engines, particularly in the high thrust engine class. Similar aims, particularly that of mass reduction, have also led to the use of hollow fixed blades in the construction of the fan flow-straightener. The techniques normally adopted for the manufacture of fan flow-straighteners involve the standard foundry practice of using cores for the hollow parts, particularly ceramic cores or soluble cores.
However, the application of these techniques to large hollow flow-straightener blades gives rise to numerous manufacturing difficulties and drawbacks, as well as to an increase in costs. For example, the use of soluble cores requires openings which have to be replugged by welding, which leads to deformations.